What is a DCP?
Digital Cinema Package
DCP (Digital Cinema Package) is the video format for the digital cinema projectors. It is the digital equivalent of a 35mm film print. It is what you send to a cinema to be able to show your spot on the big screen.
A DCP is always a folder with typically 6 files and optionally some more:
ASSETMAP: allows the cinema player to check if the files to be used for image/sound/subtitles haven't been altered
VOLINDEX: small XML file that always contains the same XML code
PackingList: (PKL_[something].xml or ___.pkl) defines which files belongs to this package
ContentPlayList: (CPL_[something].xml or ___.cpl) contains the references to the MXF files and when to use them
Audio: audio in 5.1 channel format, uncompressed, in an MXF file (there can be multiple ones, for different languages)
Video: video in JPEG2000 format, in an MXF file
Subtitles: subtitle files can be added in multiple languages